Separation of European flat oyster, Ostrea edulis, haemocytes by density gradient centrifugation and SDS-PAGE characterisation of separated haemocyte sub-populations.

A two-step gradient centrifugation with Percoll and Ficoll successively as density medium was developed to separate European flat oyster, Ostrea edulis, haemocytes into three sub-populations representing granulocytes, large hyalinocytes and small hyalinocytes, respectively. After a Percoll gradient centrifugation, granulocytes and agranulocytes were separated and a pure fraction of granulocytes was obtained. The agranulocytes were further separated by centrifugation through a Ficoll gradient, and two haemocyte subpopulations representing large hyalinocytes and small hyalinocytes were obtained. No significant impact on the haemocyte viability was detected after separation with this two-step density gradient centrifugation. The three haemocyte sub-populations showed different protein patterns in SDS-PAGE.